This invention relates to a sheet separating apparatus for removing sheets one by one from a stack of sheets.
The invention has application, for example, to a currency note picking mechanism for extracting notes from a currency cassette used in an automated teller machine (ATM). As is well known, in operation of an ATM a user inserts a customer identifying card into the machine and then enters certain data (such as codes, quantity of currency required or to be paid in, type of transaction, etc.) upon one or more keyboards associated with the machine. The machine will then process the transaction, update the user's account to reflect the current transaction, dispense cash, when requested, extracted from one or more currency cassettes mounted in the machine, and return the card to the user as part of a routine operation.
One known kind of sheet separating apparatus is represented by a currency note picking mechanism which incorporates pivotably mounted vacuum operated suckers disposed adjacent an associated currency cassette. The suckers are arranged to draw part of an end note of a stack of notes out of the cassette and into a position where this note is engaged by cooperating drive rollers. This known apparatus has the disadvantages that the suckers tend to wear and harden with age and that the apparatus may not operate reliably with torn notes.
Other known kinds of sheet separating apparatuses incorporate a rotating suction drum arranged to engage the end sheet of a stack and to draw this sheet away from the stack as the drum rotates. Problems have been experienced with known apparatuses of this kind in that there is a tendency for double feeding of notes from a stack to take place, particularly if the sheets have tears therein, unless special precautions are taken.